Conventionally, optical fibers have waveguide modes which are shaped differently from integrated optic waveguides to which they are optically connected. To provide an efficient optical coupling between the optical fibers and the integrated optic waveguides, a mode converter is required. Known mode converters include tapered waveguides and GRIN (GRadient INdex) lenses. Examples of known tapered waveguides may be found in U.S. Pat. Nos. 5,854,868 (Yoshimura et al.), 5,265,177 (Cho et al.), and 5,009,475 (Knudson).